Semiconductor fabrication systems are under constant pressure to increase throughput. This pressure is due to many factors, including the expense associated with operating semiconductor fabrication equipment and the desire to maximize the yield of substrates processed in the equipment.
A semiconductor fabrication system can include various stations and pieces of equipment housed in a clean room. For example, such a system can include reactors, robots for handling semiconductor substrates and cassettes which hold the substrates, input/output ports in system front-ends for bringing substrates into and sending substrates out of the system, storage units, metrology tools, etc. Each station or piece of equipment has the potential to cause a bottleneck to the flow of substrates through the system, thereby degrading the throughput of the system as a whole.
Accordingly, a need exists for apparatus and methods that minimize bottle-necks in a semiconductor fabrication system.